A hydraulic circuit is disclosed for use with a powertrain having an engine, a transmission, and an output transfer group. The hydraulic circuit may have a first sump configured to collect fluid drained from the transmission, and a second sump configured to collect fluid drained from the output transfer group. The hydraulic circuit may also have a primary pump configured to draw fluid from the first sump and generate at least one flow of pressurized fluid directed to the transmission and to the output transfer group.

A drag torque reduction device for an automatic transmission includes a hydraulic controller with a diversion for excess cooling oil into an oil sump that is positioned upstream of a radiator relative to a flow of fluid to the radiator. The diversion includes a temperature-dependent, switchable aperture and a switching valve. The temperature-dependent, switchable aperture is configured to close above a temperature threshold. The switching valve is configured to close above a threshold pressure.

A method for rocking a vehicle free. The vehicle comprises a drive aggregate (2), a transmission (4), shifting elements (10), and a starting element (5). The rocking free process is carried out as a function of actuation of an accelerator pedal (11) by the driver or a torque delivered by the drive aggregate (2) as a function of the actuation of the accelerator pedal. The shifting element (10) is controlled such that reduced actuation of the accelerator pedal or reduced torque delivered by the drive aggregate (2), reduces a control pressure of the shifting element (10) of the transmission (4) down to a filling pressure or a pressure that corresponds to the filling pressure, and increased actuation of the accelerator pedal or increased torque delivered by the drive aggregate (2), increases the control pressure of the shifting element (10) and the shifting element is operated in a slipping mode.

A hydraulic pressure control method for a transmission includes determining whether a current shift range is among a plurality of shift ranges, setting a dither frequency of a pressure control solenoid valve of a hydraulic circuit for the transmission to a predetermined first frequency when the current shift range is a predetermined first range, and setting the dither frequency of the pressure control solenoid valve to a predetermined second frequency when the current shift range is a shift range other than the first range.

A method for conveying a fluid of a fluid circuit by means of an electric motor-powered fluid pump of a motor vehicle, in particular an oil pump, wherein by means of the fluid pump a fluid pressure of the fluid circuit is adjusted to a target pressure, and wherein an actual pressure of the fluid is determined without a pressure sensor.

A method for shifting a multi-speed transmission for transmitting rotation between an input shaft and an output shaft for a marine vessel. The method includes providing a multi-speed transmission having first and second gears engaged by actuating first and second clutches, and providing first and second pressure sensors that measure first and second pressures within the first and second clutches, respectively. The method further includes performing a first shift from the first gear to the second gear by de-actuating the first clutch a first delay after the second clutch is actuated, then measuring the first and second pressures and determining a first shift pressure at which the first and second pressures are substantially equal while performing the first shift. The method further includes comparing the first shift pressure to a first pressure threshold range and adjusting the first delay when the first shift pressure is outside the first pressure threshold range.

A gear-shift control data generation method executed by an execution device in a state where relational regulation data used for regulating a relationship between a state of a vehicle and an action variable associated with an operation of a transmission is stored includes a process for acquiring the vehicle state, a process for operating the transmission, a process for assigning, based on the vehicle state, a higher reward when a characteristic of the vehicle satisfies a criterion than when the characteristic does not satisfy the criterion, and a process for updating the relational regulation data by inputting, to an update mapping, the vehicle state, a value of the action variable, and a reward corresponding to the operation. The update mapping outputs the relational regulation data that is updated to increase an expected profit for the reward when the transmission is operated according to the relational regulation data.

A hydraulic pressure calculation apparatus is applied to a gear shifting system including a transmission configured to switch between a connected state and a disconnected state of a friction engagement element depending on a hydraulic pressure supplied from a hydraulic circuit, and a hydraulic controller configured to control the hydraulic circuit. The hydraulic pressure calculation apparatus includes a memory and a processor. The memory stores pieces of mapping data of a plurality of phases obtained by dividing a period from a start to an end of switching between the connected state and the disconnected state of the friction engagement element. Each piece of the mapping data defines a mapping. The processor is configured to output, as an output variable, an estimated hydraulic pressure variable indicating an estimated value of an actual hydraulic pressure supplied from the hydraulic circuit to the friction engagement element.

A gear-shift control data generation method executed by an execution device in a state where relational regulation data used for regulating a relationship between a state of a vehicle and an action variable associated with an operation of a transmission is stored includes a process for acquiring the vehicle state, a process for operating the transmission, a process for assigning, based on the vehicle state, a higher reward when a characteristic of the vehicle satisfies a criterion than when the characteristic does not satisfy the criterion, and a process for updating the relational regulation data by inputting, to an update mapping, the vehicle state, a value of the action variable, and a reward corresponding to the operation. The update mapping outputs the relational regulation data that is updated to increase an expected profit for the reward when the transmission is operated according to the relational regulation data.

An electronic control unit engages two of friction engagement elements provided in an automatic transmission in a neutral range. The electronic control unit disengages one of the two friction engagement elements engaged in the neutral range at the time of starting gear stage switching of an auxiliary transmission from a low-speed gear stage to a high-speed gear stage in the neutral range, and re-engages the friction engagement element that has been disengaged when determining that the gear stage switching has been completed.